With the rapid development of display technology, there are increasingly high requirements for display performance or characteristics such as display resolution and response time. In this case, with the development of 3D display technologies and as the size of a display is increasing, there are increasingly high requirements for mobility of thin film transistor (TFT) provided in an array substrate of a display.
The TFT comprises: a gate electrode, a gate insulating layer, an active layer, a source electrode and a drain electrode. The aforementioned mobility of TFT actually refers to the average drift velocity of carriers (electrons and holes) in the active layer of the TFT under per unit electric field. At present, active layers made of amorphous silicon can no longer meet the requirements for mobility, while metal oxide materials with higher mobility are attracting more attention. The manufacturing process of TFT in conventional techniques which uses metal oxide as active layer material has the following problem: mask process performed on source/drain electrode in conventional process is to use acid to etch patterns, but the metal oxide material is generally not acid-proof, therefore, conventional process will corrode part of the active layer which affects the performance of the device. To solve this problem, an etching stopper layer which is acid-resistant is usually used to cover the channel region of the active layer to protect the active layer from being corroded. However, it adds one more mask process, which makes the mask process complicated.